On Saturday night, Jason Hammel one-hit the Atlanta Braves. This week in By The Numbers we break down Hammel’s performance to see exactly why he was so dominant. This season Hammel has been a five-pitch pitcher using a four-seam fastball (FF), two-seam fastball (FT), slider (SL), curveball (CU) and changeup (CH). The graphic below shows Hammel’s pitch arsenal on Saturday night. The size of the circles indicates usage of the pitch type and the color indicates velocity. In the graphic, the concern is not where a pitch actually ended up, but how it got there. The point of view from the catcher’s eyes and the axes represent change in horizontal and vertical location due to spin, not absolute location. It is important to note that horizontal movement that is positive moves away from right-handed batters while negative horizontal movement is directed towards right-handed batters. Change in location compares a pitch’s final location at the front of the plate as opposed to where it would be expected to end up given no spin at all. Graphs and analysis after the jump.

Jason Hammel Arsenal on 06-16-2012

The big change in Hammel’s aresenal in 2012 is the increased use of his two-seam fastball (FT) which has enabled him to induce more ground balls than he ever has previously in his career. This pitch had tremendous horizontal movement on it Saturday night. It had significant late run which caused it to move into right handed hitters and away from left handed hitters. The end result was weak contact on both sides of the plate all night. Besides the movement of his pitches, Hammel’s location was also excellent on Saturday night. The below graphic shows the location of pitches (from the catchers point of view) that Hammel threw to lefties and righties on Saturday. In particular Hammel was masterful at pitching on the outside corner of the strike zone to lefties. His ability to keep the ball down on both sides of the plate was also excellent resulting in 10 ground ball outs.

All told Hammel got hitters to swing and miss on 17 of his 103 pitches on Saturday night (16.5%). For comparison sake, the MLB average swing and miss rate induced by starting pitchers is 8.5% and the current MLB starting pitcher leader is Cole Hammels at 12.6%. Simply put Hammel’s stuff was filthy and his slider was the swing and miss star. He only threw it 20 times on Saturday night but batters swung and missed on it 7 of those 20 times (35%). The dominance of his slider is highlighted in the graphic below which shows the swinging strikes recorded on each of Hammel’s five pitches.

Hammel had his good stuff on Saturday night, I hope everyone got to enjoy it. Games where a pitcher gets hitters to swing and miss on ~17% of his pitchers are rare, and its not a coincidence it happened in a interleague game where pitchers had to hit. The Orioles front office should continue to receive credit for moving Guthrie to acquire Hammel who continues to show that he is the Orioles best starting pitcher this season. Lets hope in the future Jason keeps going HAM.